This application is related to Japanese Patent Application No. Hei 11(1999)-370778 filed on Nov. 18, 1999, whose priority is claimed under 35 USC xc2xa7119, the disclosure of which is incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to an elastic fine tube which is light-transmissive and flexible and which has a fine flow channel, its production process and an analyzer using the elastic fine tube.
2. Description of Related Art
A sheath flow cell has been generally utilized in blood cell counters because it serves to detect blood cells one by one without coincidence loss of the blood cells. The sheath flow cell means a cell which defines a fine sample flow that is hydrodynamically focused in a sheath liquid and that has a diameter of several tens of micrometers. If a tube as fine as the sample flow can be produced, then it will be possible to detect separate blood cells one by one without utilizing the sheath flow cell.
With recent development of a micro-machining technique, fine flow channels are increasingly formed by etching. This technique enables the formation of flow channels having a rectangular cross section with a side of several micrometers to several hundreds of micrometers. However, the flow channels, when used for blood cell counters, need to be provided with affinity for blood cells coming from living bodies by treating their inside walls with coating or the like.
Besides, the flow channels formed by the micro-machining technique inevitably have undulations on the inside walls. For this reason, fine particles that are flown in the flow channels adhere to the undulations, and smooth flow of the particles cannot be obtained. In addition, a huge investment in a plant and equipment is required for implementing this technique.
On the other hand, commercially available are various kinds of fine tubes made of silicone, Teflon and others. However, the commercially available tubes are limited in size, and the smallest ones are about 0.5 mm in internal diameter and 1 mm in external diameter.
Japanese Patent Publication No. HEI 6(1994)-52265 discloses a technique for producing a tube by extrusion molding and changing the tube into a finer tube by heating and stretching.
However, the formation of a tube by extrusion and stretching involves quenching, and residual stress makes it extremely difficult to obtain a transparent tube with a small birefringence. It is inherently difficult to produce an fine tube of a elastic material such as silicone rubber by stretching.
The present invention has been made in view of the above-mentioned circumstances, and an object of the invention is to provide an elastic fine tube which is light-transmissive and flexible and has a fine flow channel therethrough. Also the invention provides a process of producing the elastic fine tube as well as an analyzer using the elastic fine tube.
The elastic fine tube of the present invention is characterized by including a light-transmissive body of an elastic material having at least one flow channel therethrough so that a particle not more than 300 xcexcm in diameter passes through the flow channel, and a first connecting conduit and a second connecting conduit which are connected to the body and communicated with both ends of the flow channel of the body, respectively.
The process of producing the elastic fine tube of the present invention is a process of producing an elastic fine tube which includes a light-transmissive body of an elastic material having at least one flow channel therethrough and a first connecting conduit and a second connecting conduit which are connected to the body and communicated with both ends of the flow channel of the body, respectively, the process comprising the steps of preparing a mold having at least one elongated groove passing both ends of an elongated core through the first and second connecting conduits respectively supporting the first and second connecting conduits at both ends of the groove in such a manner that the first and second connecting conduits and the core are substantially coaxial with respect to a longitudinal axis of the groove of the mold and one end of each of the first and second connecting conduits is rested in the groove pouring a fluid polymer resin to be cured into the groove of the mold curing the fluid polymer resin to form a molded form taking the molded form out of the mold and taking the core out of the molded form.
Further, the particle analyzer of the invention is characterized by including the above elastic fine tube; a liquid feed section for feeding a particle suspension into the elastic fine tube; and a detection section for measuring optical information of particles running through the elastic fine tube.
These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.